I've been searching the forums, and I see no fix for this, just various work-arounds. If using RealDrums, the midi count-in is virtually inaudible, no matter what volume setting is chosen in Preferences for the count-in.
Interestingly, in the piano-roll view, one can edit the volume of the count-in, and when clicked with the cursor, those piano roll count-in notes are louder. But on actual playback, no change on count-in volume occurs.